This is a multi-national trial. The trial aims to study the long-term safety of LUM-201 in subjects with Idiopathic Pediatric Growth Hormone Deficiency (iPGHD). This study will also assess pharmacodynamics and efficacy response to therapy with LUM-201.

An Extension Study to Monitor Long-Term Safety of LUM-201 Treatment in Children with Idiopathic Growth Hormone Deficiency. This study will last for up to 36 months to allow collection of additional long-term safety and efficacy data related to LUM-201 treatment in the pediatric patient population. Subjects will enter into this trial after successful participation in a prior LUM-201 study. This study will consist of visits every 6 months through three years.

There are a total of 7 in-person visits with a follow-up phone call between visits. At the clinic visits, subjects will have a physical exam and blood collection as well as efficacy assessments.

Inclusion Criteria:

• Parent/caregiver must sign the informed consent, and the subject must sign the assent, as applicable.
• Must have successfully participated in a pediatric LUM-201 GHD study through at least the 12-month visit, and be eligible for continuation of treatment, pending all other enrollment criteria are met.

Exclusion Criteria:

• Medical or genetic condition that, in the opinion of the PI and/or MMs, adds unwarranted risk to the use of LUM-201
• Has planned or is receiving current long-term treatment with medications known to act as substrates, inducers, or inhibitors of the cytochrome system CYP3A4 that metabolizes LUM-201. Subjects receiving shorter-term (two weeks or less) treatment with these medications should be evaluated on case-by-case basis by the PI in consultation with the MMs.